Dual-energy CT(DECT)における被検者被ばく線量の最適化を実現させることを目的に,DECTの被ばく・画質評価,自動露出機構(AEC)の動作特性の解析,仮想非造影画像の精度に関する物理的・臨床的評価を実施した.その結果,DECTはSingle-energy CT(SECT)と比較して画質はわずかに劣るものの,より低被ばくでの撮影を実施できることが確認された.また,TCMのDECTにおける動作特性はSECTとは異なり,特に体格の大きい被検者において不適切であった.また,仮想非造影イメージングの精度は,収集プロトコル,被検者の体格,造影剤濃度により異なることが確認された.
To optimize patient dose in dual-energy computed tomography (DECT), radiation dose and image quality, operating characteristics of automatic exposure control (AEC), and physical and clinical assessment of attenuation values in virtual non-contrast (VNC) images were evaluated. Although DECT provides images which have image quality inferior to single-energy CT (SECT), it can be performed with less radiation dose. The combination of AEC and DECT is unsuitable for obese patients because it tends to provide lower radiation dose and higher image noise levels than the combination of AEC and SECT. Attenuation in VNC images differs depending on the acquisition protocol, patient size, and contrast agent concentration.